• Mauro Carvalho Chehab's avatar
    Kconfig: disable Media Controller for DVB · 6cea28d0
    Mauro Carvalho Chehab authored
    Since when we start discussions about the usage Media Controller for
    complex hardware, one thing become clear: the way it is, MC fails to
    map anything different than capture/output/m2m video-only streaming.
    
    The point is that MC has entities named as devnodes, but the only
    devnode used (before the DVB patches) is MEDIA_ENT_T_DEVNODE_V4L.
    Due to the way MC got implemented, however, this entity actually
    doesn't represent the devnode, but the hardware I/O engine that
    receives data via DMA.
    
    By coincidence, such DMA is associated with the V4L device node
    on webcam hardware, but this is not true even for other V4L2
    devices. For example, on USB hardware, the DMA is done via the
    USB controller. The data passes though a in-kernel filter that
    strips off the URB headers. Other V4L2 devices like radio may not
    even have DMA. When it have, the DMA is done via ALSA, and not
    via the V4L devnode.
    
    In other words, MC is broken as a whole, but tagging it as BROKEN
    right now would do more harm than good.
    
    So, instead, let's mark, for now, the DVB part as broken and
    block all new changes to MC while we fix this mess, whith
    we hopefully will do for the next Kernel version.
    Requested-by: default avatarLaurent Pinchart <laurent.pinchart@ideasonboard.com>
    Signed-off-by: default avatarHans Verkuil <hans.verkuil@cisco.com>
    Acked-by: default avatarLaurent Pinchart <laurent.pinchart@ideasonboard.com>
    Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@osg.samsung.com>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    6cea28d0
Kconfig 5.95 KB